The invention relates to a device for depositing a free-flowing medium on the surface of an object along a depositing curve deviating from the circular shape.
Metal tins whose contents are to be packed in an airtight and/or watertight manner are mostly closed with the lid placed on by way of beading the edge of the lid. The lid edge is provided with a rubber coating in order to ensure the required tightness. With round lids, i.e. corresponding to the circular shape, the rubber coating of the edges does not cause any problem. In DE 21 56 238 there it is disclosed for this purpose to rigidly arrange a nozzle and to let a lid rotate about its axis. In order to obtain a uniform deposit the angular speed, which the region to be deposited has, should be as constant as possible.
The depositing of sealing material with noncircular lids is more of a problem. For this it is already known to deposit the fluid sealing means onto the lid edge with a stamp or with a multitude of nozzles (needle valves) arranged next to one another corresponding to the shape of the lid. Both methods do not lead to a satisfactory result. The so-called stamping method does not always lead to a uniform deposit so that the quality of sealing is not satisfactory. With a multitude of nozzles, although a relatively uniform deposit is obtained, there is however the danger that disturbances occur and already with the breakdown of one nozzle the uniformity of the deposit is no longer ensured. Furthermore there arises difficulties when the interruption of operation occurs since the coating medium hardens.
From DE 195 12 649 there has become known a device with which the receiver for a lid is displaceably mounted and comprises a toothed disk corresponding to the contour of the lid, whose neutral line corresponds to the center line of the lid edge to be rubber coated. With the toothed disk there meshes a gearwheel which revolves synchronously with a main drive shaft. With the main drive shaft two radial cams are connected in a rotationally rigid manner, wherein the first radial cam so adapts the position of the square toothed disk with respect to the gearwheel that the teeth of the square toothed disk are always in engagement and the second radial cam displaces the axis of the gearwheel such that the opening of the injection nozzle is continuously located over the center line of the lid edge. This known device although ensuring a uniform deposit by way of a constant relative speed between the stationary depositing nozzle and the moved lid edge, the mechanical effort however is not unconsiderable. Furthermore it requires a complicated equipping and removal of the lid into or out of the receiver device.